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Home > Products > Discrete Semiconductor Products > Transistors > Bipolar (BJT) > Single Bipolar Transistors

STMicroelectronics MJ2501

Name: MJ2501
Brand: STMicroelectronics
SKU: MJ2501
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: MJ2501

Manufacturer:: STMicroelectronics

Category:: Single Bipolar Transistors

Package:: TO-204AA, TO-3

Datasheet:: MJ2501.pdf

Description:: TRANS PNP DARL 80V 10A TO-3

Quantity:: RFQ Add To RFQ list

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Product details

Overview

MJ2501 from STMicroelectronics is a silicon epitaxial-base PNP power Darlington transistor in TO-3 metal package, designed for high-current linear and switching applications. It delivers 10 A collector current, 80 V VCEO, 150 W total dissipation at Tc ≤ 25 °C, and DC current gain (hFE) ≥ 1000 at IC = 5 A, used in audio power amplifiers and low-voltage DC motor drivers.

For engineers reviewing the MJ2501 datasheet, MJ2501 pinout, MJ2501 application, or MJ2501 equivalent, key selection criteria include sustained VCEO(sus) of 80 V at IC = 100 mA, VCE(sat) ≤ 4 V at IC = 10 A/IB = 50 mA, thermal resistance Rthj-case ≤ 1.17 °C/W, and complementary pairing with MJ3001 for push-pull output stages.

Technical Context

The MJ2501 implements a monolithic Darlington configuration with integrated base-emitter resistors (R1 ≈ 10 kΩ, R2 ≈ 150 Ω), enabling simplified biasing and improved turn-off speed versus single transistors. Its PNP polarity and negative voltage/current conventions require mirrored circuit design relative to NPN counterparts like MJ3001.

Rated for Tj(max) = 200 °C and Tstg = −65 to 200 °C, it supports high-temperature operation in industrial power switching and audio amplifier output stages where thermal robustness and sustained voltage blocking are critical.

Key Specifications

Parameter	Value and Actual Design Meaning
VCBO	80 V - Maximum reverse collector-base voltage before breakdown; defines safe operating area in switching transitions.
VCEO	80 V - Maximum collector-emitter voltage with open base; sets upper limit for supply rail in linear amplifier output stages.
IC	10 A - Continuous collector current capability; supports >20 W audio output into 4 Ω loads with proper heatsinking.
Ptot	150 W at Tc ≤ 25 °C - Total power dissipation limit; requires thermal interface resistance ≤ 0.5 °C/W to maintain Tj ≤ 200 °C at full load.
hFE	≥1000 at IC = 5 A - High DC current gain reduces required base drive current, easing driver stage design.
Rthj-case	1.17 °C/W - Junction-to-case thermal resistance; determines minimum heatsink thermal resistance for given power and ambient conditions.

Pinout & Package

Package: TO-3 metal case (JEDEC standard), dimensions per mechanical drawing: D = 8.32–8.92 mm (collector tab), E = 19.00–20.00 mm (body width), U = 38.50–39.30 mm (overall length). Mounting hole centered on collector tab.

Pin/Terminal	Circuit Role	Design Meaning
Collector (Tab)	Main current-carrying terminal, electrically connected to metal case	Must be electrically isolated from heatsink unless circuit design intentionally references collector to chassis ground.
Base	Control input for Darlington pair	Internally biased via R1 (10 kΩ) and R2 (150 Ω); accepts low-current drive, reducing need for external pre-driver stage.
Emitter	Output reference terminal	Provides common return path; polarity is reversed vs. NPN devices-emitter connects to positive rail in high-side switch configurations.

Key Features

Feature	Design Value
Monolithic Darlington structure	Integrates driver and output transistors on one die, eliminating interconnect inductance and improving switching consistency.
Integrated base bias resistors	R1 ≈ 10 kΩ and R2 ≈ 150 Ω enable direct TTL/CMOS-level drive without external base resistor network.
High VCEO(sus) rating	80 V sustaining voltage at IC = 100 mA ensures reliable operation during inductive load flyback in DC-AC converters.
TO-3 metal package	Enables direct mechanical mounting to large heatsinks with low thermal impedance, supporting continuous 10 A operation under forced-air cooling.

Applications

Audio Power Amplifier

DC-AC Converter

Use Scenario: Output stage in Class AB audio amplifiers delivering 20–50 W into 4–8 Ω speakers.

IC Role / Device Role / Timing Role: PNP Darlington output transistor in complementary push-pull pair with MJ3001.

Use Value: High hFE ≥1000 reduces driver-stage loading; 150 W dissipation enables sustained RMS output without thermal foldback.

Use Scenario: High-current switching element in half-bridge inverters converting 24–48 V DC to 50/60 Hz AC.

IC Role / Device Role / Timing Role: Low-side switch in transformer-coupled inverter topology with snubber-assisted turn-off.

Use Value: 80 V VCEO(sus) withstands inductive kickback during dead-time; TO-3 thermal mass buffers transient junction temperature spikes.

Low-Voltage DC Motor Driver

General Power Switching

Use Scenario: H-bridge arm for brushed DC motors in battery-powered industrial tools (12–36 V).

IC Role / Device Role / Timing Role: High-current PNP switch controlling motor direction and braking via emitter-follower configuration.

Use Value: Integrated base resistors allow direct microcontroller GPIO control; 10 A IC rating supports peak stall currents up to 15 A with pulse duty cycling.

Use Scenario: Main switching device in regulated DC power supplies and solid-state relays.

IC Role / Device Role / Timing Role: Series pass transistor in linear regulators or high-side switch in programmable current sources.

Use Value: 200 °C max junction temperature permits operation in sealed enclosures; 1.17 °C/W Rthj-case simplifies thermal design for 50–100 W systems.

Equivalent & Alternatives

The following parts are listed as comparable options for similar PNP power Darlington transistor applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
TIP2955	Lower hFE (≥75 at IC = 4 A), higher VCE(sat) (≤ 4 V at IC = 8 A), same TO-3 package	Less suitable for low-drive applications; requires stronger base drive than MJ2501	Select when cost sensitivity outweighs gain and saturation voltage requirements
BDX53C	TO-126 plastic package, lower Ptot (60 W), VCEO = 60 V, hFE ≥ 750 at IC = 3 A	Limited to medium-power applications; not recommended for >30 W continuous dissipation	Select only for space-constrained PCB layouts where TO-3 mounting is impractical

Compared with TIP2955 and BDX53C, the MJ2501 provides superior current gain and thermal handling for high-fidelity audio and industrial motor control, but requires careful isolation of its conductive metal case and complementary NPN pairing for balanced operation.

Availability

MJ2501 is available at Aetrix Electronics and suitable for audio power amplifiers, DC-AC converters, and low-voltage DC motor drivers requiring stable component supply across extended production cycles.

Supply support for MJ2501 includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

STMicroelectronics is a global semiconductor leader headquartered in Geneva, designing and manufacturing analog, digital, and mixed-signal ICs, discrete devices, and MEMS sensors for industrial, automotive, and consumer markets.

The MJ2501 belongs to ST's legacy power bipolar transistor family, engineered specifically for high-reliability linear and switching power applications demanding ruggedness, thermal stability, and proven field performance.

FAQ

Is MJ2501 still in active production?

No - MJ2501 is marked "Obsolete Product(s)" in the official STMicroelectronics datasheet dated September 2003. It remains available through authorized legacy distributors and Aetrix Electronics' long-term inventory program for replacement and maintenance of installed equipment.

Can MJ2501 be used without a heatsink?

No - even at modest power levels, the MJ2501 requires a heatsink. At 10 A and 3 V VCE, dissipation exceeds 30 W; with Rthj-case = 1.17 °C/W, junction temperature would exceed 200 °C without additional thermal resistance management.

What is the purpose of the internal 10 kΩ and 150 Ω resistors?

These resistors form a built-in Darlington base bias network: the 10 kΩ resistor pulls the driver transistor base toward emitter potential for turn-off, while the 150 Ω resistor limits base current to the output transistor, enabling direct logic-level drive and improving switching consistency.

How does MJ2501 differ from MJ3001 in circuit implementation?

MJ2501 is PNP and MJ3001 is NPN; they share identical voltage/current ratings but opposite polarity. In push-pull output stages, MJ2501 sinks current from the load to ground (or negative rail), while MJ3001 sources current from the supply rail - requiring mirrored biasing and complementary layout.

MJ2501 Specifications

Product attributes: Attribute value

Manufacturer:: STMicroelectronics

Series:: -

Package/Case:: TO-204AA, TO-3

Packaging:: Bulk

Product Status:: Obsolete

Transistor Type:: PNP - Darlington

Current - Collector (Ic) (Max):: 10 A

Voltage - Collector Emitter Breakdown (Max):: 80 V

Vce Saturation (Max) @ Ib, Ic:: 4V @ 50mA, 10A

Current - Collector Cutoff (Max):: 1mA

DC Current Gain (hFE) (Min) @ Ic, Vce:: 1000 @ 5A, 3V

Power - Max:: 150 W

Frequency - Transition:: -

Operating Temperature:: 200°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Chassis Mount

Supplier Device Package:: TO-3

MJ2501 FAQ

1.How can I place an order for MJ2501 through Aetrix?

Please submit a Request for Quotation (RFQ) for MJ2501 on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.

2.Are the price and stock information for MJ2501 reliable?

The price and inventory of MJ2501 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MJ2501 is usually 5 days.

3.What payment methods are accepted for MJ2501?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MJ2501 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for MJ2501?

MJ2501 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your MJ2501 order is processed, you will receive an email with the shipment details and tracking number.

Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.

5.How can I obtain technical support or documentation for MJ2501?

For technical support, including MJ2501 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MJ2501 requirements.

6.How does Aetrix verify that MJ2501 is sourced from the original manufacturer or authorized distributors?

All MJ2501 products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that MJ2501 meets industry standards.

7.What is the process for return or replacement of MJ2501?

All MJ2501 units undergo pre-shipment inspection (PSI). If there is an issue with MJ2501, returns or replacements are accepted under the following conditions:

1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.

2.The issue is reported within 90 days of delivery.

3.The MJ2501 part is unused and in its original packaging.

Return procedure for MJ2501:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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